Monday, October 27, 2008

Once again, as the days get shorter and cooler, the signal for the deciduous plants to shut down and lose their leaves is upon us. This process creates the most colorful display of most plants' year as the leaves turn shades of yellows to oranges (carotenoid pigments) or reds to purple (anthrocyanin pigments). Sunny, dry Autumn days with cool nights bring about the best fall colors so with our over 5-1/2" of rain this month we are not having a spectacular display this year. Some plants have the genetics to display beautiful fall attire here each year, however!Scarlet Oak (Quercuscoccinea) is one of the most consistent fall colors at Powell Gardens but a challenge to transplant. Look for our three trees in the parking lot of the Chapel. Scarlet oaks must have good drainage and lower pH soils.A closeup of the Scarlet Oaks leaves shows their intense reds, which are anthrocyanin pigments.

Northern Red Oaks (Quercusrubra) grow wild at Powell Gardens and have variable colors in fall, from golden-olive to burnt reds as shown on this branch. This tree is wild adjacent to the Chapel's parking lot.

Shingle Oaks (Quercusimbricaria) have fall colors that can be very complex on close inspection but are overall brownish from a distance.

Swamp White Oaks (Quercusbicolor) will never win a fall color pageant and are golden-olive-tan at best.

Flowering Dogwoods (Cornusflorida) are our most reliable small or understory tree for fall color. I would plant them even if they never bloomed! The fall color lasts at least a month and changes from chocolaty purple to red as the green chlorophyll breaks down in the leaf. This slow process allows the anthrocyanins to glow red once the green chlorophyll is gone.

The 'Ozark Spring' Flowering Dogwood has one of the best reds and is right on schedule. This cultivar is nearly impossible to find because it is hard to propagate. It was discovered by the late, great Kansas plantsman John Pair and has proven hardiness in Eastern Kansas. Flowering Dogwoods that originate in the western Ozarks (just two counties east) have the genetic makeup to grow well in our Greater Kansas City climate.

This Flowering Dogwood is still in its purply stage and is heavily studded with red fruit. The fruit of dogwoods is on the ends of the branches in bird beak-sized form as a quick snack to fuel fall migration. It is so rich in fats for the birds that it will fall and rot if uneaten. Of course the birds help disperse the seeds of the dogwood and Flowering Dogwoods have begun to naturalize in woodlands around Kansas City.

Here is a closeup of a Flowering Dogwood with ripe fruit adjacent to its round, chalky gray flower bud for next spring.

The variegated leaved Flowering Dogwoods can have complex colors in fall as the white or yellow summer variegation usually reveals pinkish fall color! This is the cultivar'Cherokee Sunset' which has yellow and green variegated leaves and red-pink flowers.

Here Ginkgo (Ginkgo biloba) (left small tree in yellow) and a Flowering Dogwood (right small tree) are back lit against a mass of Variegated Maiden Grass (Miscanthussinensis 'Variegata')

Ginkgos are one of our most reliable fall colors in yellow! The pigment is carotenoid (carot- as in carrots) so reveals yellow after the green chlorophyll is gone. This young ginkgo is growing next to variegated maiden grass.

Smooth Sumac (Rhusglabra) is another one of our consistent fall colors and is native throughout Greater Kansas City. Smooth Sumac is a rhizomatous shrub to small tree -- the rhizomatous part is why you don't see it more in landscapes. This ability to mass produce by underground runners can make it a rogue in the garden. It is perfectly at home in roadside, edge of woods or hedgerow where it can be allowed to do its thing. We planted them to make a big mass at either side of our entrance landscape (where this picture was taken).

Smooth Sumac is a dioecious shrub: in other words it is male or female. Male plants look like this in fall (without the cluster of fruit at the end of the branches).

Female sumacs are studded with cone-like clusters of fuzzy red fruit. The fruit are actually high in vitamin C and can make a good tea. On tours of our nature trail I have guests taste them (just suck on the dry fruit and spit out the seed). It can have a refreshing tangy flavor. The fruit are little used by birds until the end of winter and early spring when they become an important emergency food source during a late cold snap or snowfall.

This is the hybrid 'Autumn Blaze' Maple (Acerx fremontii), a hybrid between the Silver Maple (Acersaccharinum) and Red Maple (Acerrubrum). It is cheap to grow and being widely grown and sold. It is spectacular this year but that is often not the case and we do not recommend the tree. Red Maples (Acerrubrum) are the most commonly grown tree for planting because of their fall color. They are however difficult trees to garden with as they have voracious surface roots. They also are very subject to frost cracking (the southwest side of the trunk dies, leaving a big scar). We have a nice 'Red Sunset' Red Maple in front of the Visitor Center but this year it has just turned brown.

This is the week of peak fall color at Powell Gardens! Come see the colors of the chemistry of life (without photosynthesis there would be no life). With our 14,000 varieties of plants on display you will surely see some in great fall attire. Remember, last days and weekend to see Chapungu too!